Algebra Demystified 2nd Ed

276 algebra De mystif ieD

The equation to solve is^1

3

11

2

  +  = 

t

. The LCD is 6t.

1

3

11

2

6 1

3

1 6 1

2

6 1

3

6 1

+=

 +







= 















+

t

t

t

t

tt

t









=

+=

−−

=

3

263

22

6

t

tt

tt

t

Brandon can split the wood-pile by himself in 6 hours.

3. Worker Quantity Rate Time
   Boy 1 1/90 90
   Girl 1 1/60 60
   Together 1 1/t t

The equation to solve is^1

90

1

60

  + ^1 = 

t

. The LCD is 180t.

1

90

1

60

1

180 1

90

1

60

180 1

180 1

90

+=

 +







= 







t

tt

t

t







+ 







=

+=

=

=

180 1

60

180

23180

5 180

180

5

t

tt

t

t

t== 36

Working together, the boy and girl need 36 minutes to weed the garden.

4. Worker Quantity Rate Time
   Robert 1 1/40 40
   Paul 1 1/20 20
   Together 1 1/t t